Shubnikov-de Haas Oscillations of filled skutterudite compounds CeOs$_4$Sb$_{12}$ and NdOs$_4$Sb$_{12}$

The filled skutterudite compounds CeOs$_4$Sb$_{12}$, PrOs$_4$Sb$_{12}$, and NdOs$_4$Sb$_{12}$ are respectively a 1~K antiferromagnetic (AFM) Kondo insulator, a 1.85~K unconventional superconductor (SC), and a 1~K mean-field type ferromagnet (FM). Since SC in PrOs$_4$Sb$_{12}$ exhibits non-BCS properties, it may originate from proximity to AFM and FM quantum-critical points. Therefore, Fermi-surface measurements of NdOs$_4$Sb$_{12}$ and CeOs$_4$Sb$_{12}$ become crucial in understanding the SC pairing mechanism in PrOs$_4$Sb$_{12}$. MHz skin-depth measurements of single crystals of CeOs$_4$Sb$_{12}$ and NdOs$_4$Sb$_{12}$ were performed for temperatures down to 1.3 K and magnetic fields of up to 60 tesla in the Pulsed Field Facility at NHMFL/LANL. Proximity detection oscillator (PDO) data are taken in the 60 tesla generator-driven magnet ($\sim 1$ s) using a rotational probe. Shubnikov-de Haas oscillations were detected for various direction of the magnetic field with respect to the crystalline orientations. The results indicate that NdOs$_4$Sb$_{12}$ has similar Fermi surfaces to those of PrOs$_4$Sb$_{12}$ and LaOs$_4$Sb$_{12}$ but that the Fermi surface of CeOs$_4$Sb$_{12}$ is much different from those of the other three compounds.